Hi Simon…
Not 100% of the time.
I’m certainly not a Weber expert on V-8 engines, but my TVR Vixen 2500 has triple DCOE 40s.
I am running a stock mechanical fuel pump, which feeds into pressure regulator. I have my regulator dialed down to about 2-3 psi feeding the Webers.
Apparently Webers are very sensitive to fuel pressure, but they like to have full flow, but only at pressures about 2-3 psi.
Rocky